Limiting the Spectral Diffusion of Nano-Scale Light Emitters using the Purcell effect in a Photonic-Confined Environment

Partial suppression of the spectral diffusion of quantum dot (QD) excitons tuned to resonance of a nano-photonic cavity is reported. The suppression is caused by the Purcell enhancement of the QD-exciton recombination rate, which alters the rate of charging of the solid-state environment by the QD itself. The effect can be used to spectrally-stabilize solid-state emitters of single photons and other non-classical states of light

Bound and anti-bound biexciton in site-controlled pyramidal GaInAs/GaAs quantum dots

We present a detailed study of biexciton complexes formed in single, site-controlled pyramidal GaInAs/GaAs quantum dots (QDs). By using power dependent measurements and photon correlation spectroscopy, we identify the excitonic transitions of a large number of pyramidal QDs, exhibiting both positive and negative biexciton binding energies. Separation of charges within the QD, caused by piezoelectric fields, is believed to be responsible for the positive to negative crossover of the biexciton binding energy with increasing QD size. In particular, QDs exhibiting vanishing biexciton binding energies are evidenced, with potential applications in quantum information processing. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4765646

Integration of multiple site-controlled pyramidal quantum dot systems with photonic-crystal membrane cavities

We describe the fabrication, epitaxial growth and photoluminescence (PL) spectra of systems of site-controlled pyramidal quantum dots (QDs) integrated with photonic crystal (PhC) membrane cavities. The spectra of the individual QDs are characterized by scanning micro-PL spectroscopy, and the cavity modes are identified by polarization-resolved PL measurements and modeling. Weak coupling of systems incorporating up to four identifiable QDs with single modes of the PhC cavities is demonstrated. (C) 2014 Elsevier B.V. All rights reserved

Exciton dynamics in a site-controlled quantum dot coupled to a photonic crystal cavity

Exciton and cavity mode (CM) dynamics in site-controlled pyramidal quantum dots (QDs), integrated with linear photonic crystal membrane cavities, are investigated for a range of temperatures and photo-excitation power levels. The absence of spurious multi-excitonic effects, normally observed in similar structures based on self-assembled QDs, permits the observation of effects intrinsic to two-level systems embedded in a solid state matrix and interacting with optical cavity modes. The coupled exciton and CM dynamics follow the same trend, indicating that the CM is fed only by the exciton transition. The Purcell reduction of the QD and CM decay times is reproduced well by a theoretical model that includes exciton linewidth broadening and temperature dependent non-radiative processes, from which we extract a Purcell factor of 17 +/- 65. For excitation powers above QD saturation, we show the influence of quantum wire barrier states at short delay time, and demonstrate the absence of multiexcitonic background emission. (C) 2015 AIP Publishing LLC

Site-controlled InGaAs/GaAs pyramidal quantum dots grown by MOVPE on patterned substrates using triethylgallium

The fabrication and characterization of site-controlled InGaAs/GaAs quantum dots (QDs) made by MOVPE using triethylgallium (TEGa) on patterned {111}B GaAs substrates are reported. Results are compared to more traditional pyramidal QD structures grown employing trimethylgallium (TMGa). Several potential advantages of the use of TEGa are demonstrated, including more reproducible achievement of QD transitions with narrow (< 100 mu eV) linewidths and better spectral uniformity across patterned substrates. These features are important for QD integration in optical cavities, which require both site and spectral stringent control. (C) 2014 Elsevier B.V. All rights reserved